The diagonal relationship is shown by the elements upto how many groups only ?

Explanation

To determine how many groups show the diagonal relationship among elements, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Concept of Diagonal Relationship**:
- The diagonal relationship refers to the similarity in properties between certain pairs of elements in different periods of the periodic table. Specifically, it is observed between elements of the second period and the third period.

2. **Identify the Relevant Periods**:
- The elements in the second period include:
- Lithium (Li), Beryllium (Be), Boron (B), Carbon (C), Nitrogen (N), Oxygen (O), Fluorine (F), and Neon (Ne).
- The elements in the third period include:
- Sodium (Na), Magnesium (Mg), Aluminium (Al), Silicon (Si), Phosphorus (P), Sulfur (S), Chlorine (Cl), and Argon (Ar).

3. **Determine the Groups of Interest**:
- The diagonal relationship is typically observed between:
- Li (Group 1) and Na (Group 1)
- Be (Group 2) and Mg (Group 2)
- B (Group 13) and Al (Group 13)
- C (Group 14) and Si (Group 14)

4. **Count the Groups**:
- From the above pairs, we can see that the diagonal relationship is observed in:
- Group 1 (Li and Na)
- Group 2 (Be and Mg)
- Group 13 (B and Al)
- Group 14 (C and Si)
- Therefore, the total number of groups that show a diagonal relationship is 4.

5. **Conclusion**:
- The diagonal relationship is shown by elements up to 4 groups.

### Final Answer:
The diagonal relationship is shown by the elements up to **4 groups**.